Air-borne particle collector and method of estimating the solids in air strata



April. 26, 1949. J, H, BLACKv 2,468,021

AIR-BORNE PARTICLE COLLECTOR AND METHOD OF ESTIMATING THE SOLIDS IN AIRSTRATA' Filed Nov. 4, 1947 Patented Apr. 26, 1949 AIR BBRNE PARTICLECOLLECTOR. AND METHOD OF ESTIMATING. THE SOLIDS.

lIN AIR STRATA James H. Black, Clarke County, Ohio Application November4.-, 1947', Serial No: 783,888

(Granted under the act of March 3; 18.83, as amended'April 3.0, 1928;.370 0.-.G.' 757) 5. Claims.

Patent 1,517',1=l4discloses a dust determinator in-which theentirevolume of air to be estimated or afraction 'thereof must be pumpedthrough a filter. This is obviously impractical for outdoor work wherealarge area must be accurately determined.

One'object of the present'invention is to provide means and method toestimate accurately the dust concentration in high strata of theatmosphere;

Another obiect-isto make such a determination valid for a considerablearea; which may be miles in extent.

Another object is to make such a determination at a point removed fromany station for example anairplane, which itself'might be a source ofdust.

Another object is to provide a simply constructed particle collectorwhich may be easily towed behind an airplane.

Another object is to providea particle collector offtheaboveacharacter.which may be easily disassembledto; change filtering-elements or toweigh them.v

Briefly stated, the method comprises towing at a particular level apro-weighed particle collector, or a particle collector containing apre-weighed filtering element, behind an airplane, the particlecollector having an inlet of known area, and tow ing such a filter for ameasured distance through the particular stratum. The increase in weightof the particle collector or filtering element is then noted and theincrease is divided by the volume of air that has passed through thefilter, hence the particle concentration per unit of volume is known.The volume is calculated by multiplying the area of the collector inletby the distance traversed and converting this volume to the desiredunits.

In order to practice the method, the traverse through the air need notbe horizontal. It may be vertical or nearly so.

The filter may be launchedfronrail-airplaneand provided with a parachuteso that in its descent, the collector will take dust from every levelbetween the earth and the height fromwhichit waslaunched.

In the drawings:

Fig. 1 shows an-airplane in perspective in the: act of carrying out themethod.

Fig. 2 is .a side elevation of one form of the-air filter, partly insection.

Fig. 3 is a front elevation of the filter.

Fig. llis aview corresponding to Fig. Zshowing a modified formwhichzemploys. a oup-shapedzfilter element.-

In Fig. 1, l is an airplane, H isa-tow'rope E2 the particle collector oi-my invention which-is being'towed'behind the airplane lil'at the end'of the rope H.

length.

In Fig. 2 the collector lz -comprises a body portion 1 3: which iscomposed of a conical forward portion I4 and a cylindrical rear portionI52: In.

Fig. 3 those portions are seen to form concentric circles.

of standard diameter, for example; two inches inside diameter. Four ormore stabilizing finsiB: proj ect 'outwardly from the conical portion 14and extend from near. the neck it: to near the cylin-Approximatelywherethe cylindrical portion I 5 joins theaconicalportionMthere is afiange 20; A cage 2| is bolted to the flange 20 and itspurpose is to hold a filter element 22 which may -be made of metalscreen, silk mesh, filter paper or other suitable material at the exitor rear end of the body I 3. The rear portion 23 of the cage 2| iseither perforated or itself made of strong coarse wire mesh so that bothample mechanical support and ample filtering area is provided for thefilter 22. The latter may be of either sheet form or cylindrical. Ifcylindrical, the side Walls of the cylindrical portion 15 may be made ofwire mesh or be otherwise multi-perforated as hereinafter disclosed.

The preferred form is the modification shown in Fig. 4. The forward partof this form is identical with that shown in Fig. 2 but the flange 20 isomitted and the construction rearwardly of the line corresponding to thelocation of the The clashed section of the rope H indicates that therope may be of any desired At the forward end of portion I4 is a roundneck" 16 inwhich there is-an opening ll flange 2G in Fig. 2 isdifferent. A ring 25 which is threaded both internally and externally isscrewed into the body I3. An externally threaded ring it is screwed intoring 25 so as to leave about projecting therefrom. A recessed shoulder21 is so formed. The projecting part of ring 23 is preferablyunthreaded.

The recessed shoulder 2'! serves to retain a porous filter cup 22, whichmay be made of metal screen, paper or cloth, and to prevent it from tothe extent of receiving a plurality of screws 29 for attachment of thewall 23 to the cylindrical body i5. The rear wall retains the filterelement rim within the recessed shoulder 27.

The body l5 may also be made in other generally cup-shaped forms, forexample, a cone, the apex of which is rearwardly disposed.

In use, the air which streams into the opening I! makes its exit fromthe collector through the louvers 28 of the body l5 after having passedthrough the filter element 22 and having left on it whatever solidmatter which was in suspension.

The cup shape of the filter element 22 makes it convenient for weighingbefore and after the solid matter is deposited in it.

I claim as my invention:

1. The process of determining the dust content of outdoor air whichcomprises traversing a weighed air particle collector of suitablefineness and of known inlet area through a measured distance in air, andthen weighing the collector to ascertain the increase due to filteredsolid particles.

2. The method of estimating the dust content of the atmosphere at aparticular level which comprises towing at that level a dust collectorof known inlet area and which comprises a filtering element of knownweight of a fineness that will retain atmospheric dust, in asubstantially straight path from an aircraft for a measured distance andthen weighing the filtering element to determine the increase in weightper unit volume of air traversed.

3. A dust collector comprising a hollow body of minimum air resistancehaving a standard-sized forward opening, a plurality of stabilizing finson said body having openings therethrough for the attachment of ropeswhereby the collector may be towed in a stable manner behind anairplane, an air-porous filter element of known area capable ofretaining dust within said body substantially at the rear thereof anddemountable means for supporting said filter element without substantialinterference with its porosity for air.

4. A dust collector comprising a hollow conical portion having circularforward opening, and a hollow cylindrical portion, said cylindricalporion being detachably joined to said conical portion where the latteris widest, a flange extending outwardly on the exterior of the filter atapproximately the junction of the two portions, a cage attached to saidflange and enclosing said cylindrical portion, said cage including arear retainer of porous character, for said cylindrical portion anair-porous filter element adjacent to and supported by said rearretainer and at least one stabilizing fin extending outwardly from saidconical portion said fin having an opening for the attachment of a ropewhereby said collector may be towed through the air by an airplane andprevented from oscillating during such towing.

5. A dust collector comprising a body having a hollow conical forwardportion to present minimum air resistance and a. hollow rear cup-shapedportion adapted to contain a cup-shaped filter, said cup-shaped portionbeing detachably joined to said conical forward portion where the latteris widest, a pair of threaded concentric rings at the junction of thetwo parts of the body the outer of said rings threadedly engaging eachbody portion, the inner ring forming a recessed shoulder within saidrear cup-shaped portion, a cupshaped filter element within saidcup-shaped portion, the rim of said filter element being retained insaid recessed shoulder by said inner ring to prevent collapse of saidfilter, a detachable rear wall for said rear cup-shaped portion, saidwall also retaining said filter element rim within said recessedshoulder, and at least one stabilizing fin on the conical forwardportion of said body, said fin having an opening for the attachment of arope whereby the device may be towed by an airplane, the fin thenserving also to prevent the device from twisting the rope.

JAMES H. BLACK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 984,047 Touzalin Feb. 14, 19111,517,144 Anderson Nov. 25, 1924 2,079,474 Walsh May 4, 1937

